PORTLAND, OR – In the words of Carl Robinson, “it couldn’t have been scripted any better.”

Longtime rivals Vancouver Whitecaps FC and Portland Timbers will play for the top spot in the Western Conference on Sunday afternoon in their regular season finale at Providence Park.

KICKOFF: 1 p.m. PT | TV: TSN1 | RADIO: TSN 1040

Here are the key storylines to watch.

HIGH-STAKES CASCADIA SHOWDOWN

The winner of Sunday’s match will claim the top spot in the West and secure a bye to the Western Conference Semifinals. Vancouver would also do so with a draw.

There are also major implications in the Cascadia Cup race.

Portland would secure the Cup with a victory, while any other result would see Seattle Sounders FC emerge victorious. The stakes don’t get much bigger.

“You want to play in games that mean something,” Robinson said.

This one certainly does.

SO WE MEET AGAIN

Two years ago, Portland ended Vancouver’s season in the Western Conference Semifinals. Last year, the ‘Caps got their revenge, eliminating the Timbers’ from playoff contention – and overturning a five-goal differential to win the Cascadia Cup – in the regular season finale.

There have been some great battles over the years, and this has the makings of another.

“It seems like the rivalry boils over more and more as the years go on,” said Timbers head coach Caleb Porter. “I don’t ever forget a game. And there have been some games that have left a bad taste in my mouth looking back on the history. Yet, this is a new year.”

BATTLE OF THE NO. 10s

Sunday’s match features two of the most exciting attacking midfielders in MLS.

On one end, you have Portland’s Diego Valeri, an MLS MVP frontrunner with 21 goals and 11 assists on the season. And on the other, you have Vancouver’s Yordy Reyna, who has six goals and three assists in just 10 starts after returning from a fractured foot suffered in the preseason (coincidentally, in Portland).

Don’t be surprised if one – or both – of these guys find the scoresheet on Sunday.